The last rule from
here has all orthogonal speeds less than c/2 (plus a c/2 ship, which is just the frontend and backend without any signals). There is also a
diagonal version (first diagonal rule) at c/3 or less.
For the more general question,
this rule achieves all ships of any slope below a certain speed, although its maximum speed in any direction is quite slow, though perhaps
this one could be made to go much faster if we could make the signals bounce in the same way.
Of course, Life has every simplified speed <c/2 due to universal construction and the c/2 blinker fuse. If we could make something similar in a rule with a c/3d wickstretcher/puffer, that would be every speed except those on the border, which is (a,a+b)c/(3a+2b).
Any sufficiently advanced software is indistinguishable from malice.